How many cal is 5 eV?

5 × 3.829×10⁻²⁰ = 1.91×10⁻¹⁹ cal. About the energy of a hydrogen bond.

A molecular bond is 3.5 eV — how many cal?

3.5 × 3.829×10⁻²⁰ = 1.34×10⁻¹⁹ cal. Very small.

Why multiply by 3.83×10⁻²⁰?

eV is tiny compared to cal. 1 eV = 1.6×10⁻¹⁹ J, 1 cal = 4.184 J. 1 eV = 1.6×10⁻¹⁹/4.184 cal.

Is the conversion exact?

1 eV = 1.602176634×10⁻¹⁹ J ÷ 4.184 J/cal = 3.8293×10⁻²⁰ cal. Exact by definition.

Electronvolts (eV) to Calories (cal) Converter

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From

Precision4 dp

1 Electronvolt = 3.8293e-20 Calorie (thermochemical)

Key Formulas

Kilocalorie → Kilojoule

kJ = kcal × 4.184

Kilojoule → Kilocalorie

kcal = kJ × 0.239006

Kilowatt-Hour → Joule

J = kWh × 3600000

Joule → Kilowatt-Hour

kWh = J × 2.77778e-7

Formula

cal = eV × 3.8293e-20

One electronvolt equals about 3.829×10⁻²⁰ thermochemical calories. Since 1 eV = 1.602×10⁻¹⁹ J and 1 cal = 4.184 J, the conversion is 1 eV = 1.602×10⁻¹⁹/4.184 = 3.829×10⁻²⁰ cal. This is used in quantum chemistry and molecular physics.

Source: NIST SP 811, Table B.8

Frequently Asked Questions

Real-World Examples

A physicist noting that 10²⁰ eV equals 3.83 cal — atomic scale to food scale.

100000000000000000000 eV = 3.829 cal

A chemist calculating 10¹⁹ eV of bond energy as 0.383 cal for the molecular paper.

10000000000000000000 eV = 0.3829 cal

A student verifying that 6.242×10¹⁸ eV (1 kcal equivalent) equals 0.239 cal for the homework.

6242000000000000000 eV = 0.239 cal

A researcher analyzing 10²¹ eV of reaction energy records 38.3 cal in the lab notebook.

1e+21 eV = 38.29 cal

kcal to kj kj to kcal kwh to joules joules to kwh btu to joules calories to joules

Electronvolts (eV) to Calories (cal) Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

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